M16C1N Datasheet, PDF (72/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
10. Interrupt
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10.2 INT Interrupt
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10.2.1 INT0 Interrupt
INT0 to INT3 are triggered by the edges of external inputs. The edge polarity of INT0 to INT2 is selected
using the polarity select bit (bit 4 at addresses 005D16, 005E16 and 005F16). Input to INT0 is available
via filter with three different sampling frequencies.
As to external interrupt input, an interrupt can be generated both at the rising edge and at the falling
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edge by setting the INTi (i=0 to 3) input polarity select bit of the external input enable register (address
009616) to "1". To select both edges, set the polarity switching bit of the corresponding interrupt con-
trol register to "0" (falling edge). To select one edge, set the polarity switching bit of the corresponding
interrupt control register to either "1" (raising edge) or "0" (falling edge). Please note that when one
edge is selected using INT3, the polarity will be a falling edge.
After setting the external input enable register, clear the interrupt request bit, and then enable the
corresponding input interrupt. Moreover, you should write to the external input enable bit only under
conditions where the corresponding input interrupt is disabled.
Figure 10.10 shows the external input related registers.
External input enable register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
INTEN
Address
009616
When reset
0016
Bit symbol
Bit name
Function
RW
INT0EN INT0 input enable bit (Note 1)
0 : Disabled
1 : Enabled
RW
INT0PL INT0 input polarity select bit
0 : One edge
(Note 1)
1 : Two edges
RW
INT1EN INT1 input enable bit
0 : Disabled
1 : Enabled
RW
INT1PL INT1 input polarity select bit
0 : One edge
1 : Two edges
RW
INT2EN INT2 input enable bit
0 : Disabled
1 : Enabled
RW
INT2PL INT2 input polarity select bit
0 : One edge
1 : Two edges
RW
INT3EN INT3 input enable bit
0 : Disabled
1 : Enabled
RW
INT3PL INT3 input polarity select bit
0 : One edge
1 : Two edges
RW
Note 1: This bit must be set in condition of the INT0 pin one-shot trigger control bit (bit 6 at address 008416)="0"
(INT0 pin one-shot trigger invalid).
INT0 input filter select register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
INT0F
Address
001E16
When reset
XXXXX0002
Bit symbol
Bit name
INT0F0 INT0 input filter select bit
INT0F1
Function
RW
b1 b0
0 0 : No filter
RW
0 1 : Filter with f1 sampling
1 0 : Filter with f8 sampling
1 1 : Filter with f32 sampling ^RW
INT0F2
UART0 receive hardware
interrupt enable bit (Note 1)
0 : Disabled
1 : Enabled
RW
Nothing is assigned.
When write, nothing can be written. When read, their contents are indeterminate.
Note 1: Interrupts used for debugging purposes only. Be sure to set "0" to this bit.
Figure 10.10 External input related registers
Rev.1.00 Oct 20, 2004 page 60 of 222
REJ09B0007-0100Z